If your pet has fleas, he'll probably scratch, lick, or bite at his skin. Your furry friend might also have pale gums, hair loss, and areas on his coat that are red and irritated. Comb through your pet's fur. If you see small, fast-moving shapes, your pet has fleas. Black spots are "flea dirt," or dried blood left by the critters. Tiny white grains on the fur could be eggs.